You can also override addEventListener/removeEventListener on your element. My concern with that, and possibly an event listener change callback, is that it only works reliably for non-bubbling events.
On Thu, Nov 5, 2015 at 4:16 PM, Travis Leithead < travis.leith...@microsoft.com> wrote: > Interesting. Alternatively, you can add .onwhatever handlers, as well as > define your own overload of addEventListener (which will be called instead > of the EventTarget.addEventListener method). That way you can capture all > attempts at setting events on your element. > > -----Original Message----- > From: Mitar [mailto:mmi...@gmail.com] > Sent: Thursday, November 5, 2015 4:05 PM > To: public-webapps <firstname.lastname@example.org> > Subject: Callback when an event handler has been added to a custom element > > Hi! > > We are using message ports to communicate with our logic and are wrapping > the API into a custom element. The issue is that we would like to call > start on a message port only after user has registered an event handler on > the custom element instance. But it seems there is no way to get a callback > when an event handler is added. > > So I am suggesting that there should be a callback every time an event > listener is added to a custom element (and possibly one when removed). > > > Mitar > > -- > http://mitar.tnode.com/ > https://twitter.com/mitar_m > >